1. Field of the Invention
The present invention relates to a structure for an analogue-type electronic wrist watch, and, in particular to a structure for an electronic wrist watch equipped with a receiving device which has a built-in antenna for receiving a signal; to a mode switching structure for a multifunctional analogue wrist watch; and to a gear train modification mechanism for escaping from a condition in which it is impossible to reverse a step motor for a watch with a hand sector display.
2. Description of the Related Art
In recent years there has been a remarkable growth in portable devices using radio signals, and these have been commercialized in many fields. The field of wrist watches has been no exception, and, those utilizing radio signals, including radio-equipped watches, have been commercialized, although the number is not great. However, to use radio signals, not only it is necessary to have parts which are completely different from conventional timepiece parts, but methods to ensure that the receiving performance is not adversely affected must also be taken into consideration.
Among such parts, the antenna, which has a particularly significant influence on the performance of receiving radio signals, also is rather large in comparison with the parts of conventional wrist watches. There are also placement restrictions with respect to reception performance. In addition, there is also a space problem; i.e., installing the antenna inside the timepiece makes it difficult to make the wrist watch small.
Furthermore, enclosing the antenna in a metal casing must be avoided for ensuring good reception performance, posing a problem of design restrictions.
As a method to eliminate the above-mentioned problem areas, products with a structure in which the antenna is separated from the timepiece module have been commercialized. In one such structure the antenna is provided in a band, as disclosed in Japanese Patent Laid-open (kokai) No. 126408/1990. In another such structure the antenna is provided in the outer periphery of the timepiece casing so as to design the body of the wrist watch small and thin, as disclosed in Japanese Patent Laid-open (kokai) No. 38034/1989.
However, in the structures wherein the antenna is provided in the band or in the outer periphery of the watch casing, it is inevitable that the antenna must pass through the watch module into the casing. This is a major restriction from the aspect of both structure and reliability, if water proofing structure is provided for this part considering the environment in which the watch is used.
Also, in the case where the antenna is provided in the band, it is impossible to use a metal band because of the reception performance. A special watch band such as a leather band or the like must therefore be used. This causes the problem of restrictions in the type of watch band when designing the overall watch. In addition, replacement of the watch band must accompany the replacement of the antenna as well, increasing the overall costs. In the same manner, when the antenna is provided in the external periphery of the casing, there are significant restrictions on the design, because of linearity of the antenna and depending on the structure in which the antenna is fixed and inserted.
Accordingly, a first object of the present invention is to provide, with due consideration to the drawbacks of such conventional structures, an electronic wrist watch equipped with a receiving device wherein the connection between the antenna and the watch module is simple, there is no influence on the reception performance of the antenna, and there are also very few restrictions on the design of the watch.
Beside the above-mentioned antenna reception function, there are various other functions, such as a stop watch function, a timer function, and the like, provided to a multifunctional analogue wrist watch in addition to the main function of indicating normal time. It is common for these to carry out the specified functional operation through an ON/OFF switch for electrical contacts by manipulating an external operating member such as a push-pull button or the like.
However, the number of hands and external operating members in the watch is restricted. As the number of functions increases it is only natural to use the same hands for double duty in indicating the functions. Furthermore, in the external operating member, various functional operations are also performed using the same external operating member. Accordingly, with a multifunctional analogue wrist watch with a large number of functions, using the timepiece mode for each of these functions in turn, it is difficult to decipher what the hand is intended to indicate because the functions of the hands and the external operating members differ depending on the mode. There is therefore the problem that errors occur in the operation of the external operating member.
As a method of eliminating the above-mentioned problem areas, there are commercial products provided with a mode hand or the like to indicate the details of the function of the watch. This mode hand is driven by the operation of the external operating member to decipher the details of the hand and the details of the operation of the external operating member by indicating the watch mode for the function which is in current use.
However, in the operation of the external operating member in the above manner, a mode switching structure which indicates the mode for the function with a mode hand or the like is complicated in comparison with a switch structure using an ON/OFF operation of an electric contact. In addition, there are restrictions on the stroke of the external operating member when switching the mode, imposing structural restrictions.
Furthermore, a multifunctional analogue wrist watch is provided with plurality of gear trains and step motors for driving the various functions. The step motors are comparatively large, so that there are space restrictions when positioning the mode switching structure. In addition, from the aspect of design, there are considered various locations for the mode hand, the function hands, and also for the external operating member. There is therefore the problem that the above-mentioned mode switching structure gives rise to major restrictions with respect to the timepiece structure.
Accordingly, a second object of the present invention is to provide a multifunctional analogue watch with only minor restrictions in the location of the mode hand and the external operating member, specifically, only minor restrictions in timepiece design, yet providing a highly reliable mode-switching structure.
In addition, in order to satisfy a variety of needs of consumers, analogue electronic watches to which are added a chronograph, a multihand display calendar, a monthly display, and the like are on the market. In some analogue electronic watch of this type, a step motor is designed to turn both forward and in reverse so as to drive the hands sectorially within the display portion.
However, in the case of the electronic watch, a special pulse has to be applied to drive the step motor both forward and in reverse. Specifically, the structure is such that, in one pulse of reverse rotation, initially a forward drive pulse is applied and after the rotor is swung to the forward rotation side, the pulse for reverse use is applied.
In addition, for sector display using the forward and reverse rotations of the step motor, a stopper is always provided in a middle part of the rotary member in order to prevent the hands from moving beyond the specified range due to run away of the circuit chip. Accordingly, a reliable drive is indispensable when the week is revised, even when this stopper has been contacted. However, in the case where the stopper is contacted and the rotor halts, the stopper may prevent the rotation of the rotor in the forward direction depending on the position at which the rotor stops. A situation is therefore reached where reverse rotation is impossible.
Regarding a gear train modification mechanism for an electronic watch with a sector week display of the above-mentioned type, Japanese Patent. Laid-open (kokai) No. 8789/1991, filed by the applicant of the present invention, provides, in order to enable the step motor to escape from a condition in which the reverse rotation is impossible, a rotary member for any one of slowing-down gear trains from the rotor of the step motor to a hand wheel for a sector display section. The step motor forces the rotary member to rotate in the direction to change the rotation to reverse from forward by means of the modifying member which is linked to the external operating member, so that the step motor can rotate to escape from the condition in which reversal is impossible.
However, using the conventional device described above, it is necessary to move the modifying member in the reversing direction of the step motor to extricate the step motor from the condition in which reverse rotation is impossible. Specifically, because the modifying member must be moved to the side at which the rotary member normally acts, there is the possibility of the modifying member entering the normal action range of the rotary member.
Accordingly, even when the hand is acting normally, there is concern that the hand will be inadvertently caused to move due to pressure from the external operating member. In particular, in an electronic watch of the type with two hands provided on the same shaft for a sector display, this method of using the modifying member for the rotation requires two modifying members, making the structure of the timepiece complicated.
A third object of the present invention is to provide a simple modifying mechanism whereby the position of the hands is unaffected, except by the operation for extricating the step motor from the condition in which reverse rotation is impossible.